When using case_when in R in Databricks, why does mutate give an error?

edit

Mutate gives an error when using casewhen in R in Databricks if there is a mismatch in the number of rows or a data type issue with the input data frames. This can also happen if there are missing values or NULL values in the input data frames. It is important to check the data types of the input columns and ensure that they are compatible with each other. It may also help to check the syntax of the casewhen statement and ensure that all necessary arguments are included.